Synthesis and characterization of gallium colloidal nanoparticles.

In this work, gallium colloidal nanoparticles (Ga-Nps) were synthesized by chemical liquid deposition (CLD). This method involved the deposition of metallic atoms with organic solvents (THF, acetone and 2-propanol) in a freezing matrix of the solvent at 77K, in order to obtain core-shell Ga-Nps which were characterized by: FT-IR, UV-Vis, TEM, SAED and electrophoretic mobility measurements. TEM images revealed a wide distribution of the apparent size of the particles and apparent average size of 5.65, 8.11 and 13.87 nm for Ga-Nps obtained with 2-propanol, THF and acetone, respectively. UV spectra showed absorption bands of metal plasmons, interesting quantum size effects and plasmon absorption bands of particles aggregated to lambda(280) and lambda(325). Electrophoretic mobility allowed to evidence that nanoparticles had a negative charge as well as to observe that the zeta potential of the colloidal dispersions decreased over time, showing a significant tendency to the aggregation of Ga-Nps. The importance of the functionalization of metal nanoparticles with high dielectric constant solvents in the stabilization of colloidal systems was also observed. FT-IR spectroscopy revealed that the interaction of Ga surface with the solvent possibly produces a (GaC) bond. Experimental details, structural and thermal stability studies were also analyzed in this work. 2010. Published by Elsevier Inc.